SOAP allows business software programs to communicate over the Internet regardless of the platform on which they are based. The Understanding SOAP FAQs answer some of your most pressing questions about this technology and shed light on why SOAP is such an important topic.

The SOAP specification clearly establishes SOAP's role as a protocol for
defining a messaging system as well as remote procedure calls. Although the
O in SOAP stands for Object, nothing in the specification suggests
that the intention of SOAP is to provide any sort of object or component runtime.
To the contrary, SOAP makes no attempt to define mechanisms for object invocation,
garbage collection, and so on. SOAP does, however, provide the necessary mechanisms
for building object-oriented systems on top of its infrastructure.

Source: This FAQ is excerpted from Understanding
SOAP by Kennard Scribner and Mark C. Stiver (2000, Sams, ISBN 0672319225).
Refer to this book for more detailed information on SOAP.